Hoisting machine



Oct. 11, 1966 W. D. SYMMANK 3,2 78,058

HOISTING MACHINE Filed May 18, 1965 2 Sheets-Sheet 1 i l f 7i .f f' 'y l ,4 l, n, if" fJ .jij .4

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INVENTOF? WILLIAM DANIEL SY/VIPMNH Oct. 11, 1966 w. D. sYMMANK HOISTING MACHINE 2 Sheets-Sheet 2 Filed May 18, 1965 /NVENTOR WILL IAM DAN/EL SYMMA/V/f United States Patent O M 3,278,058 HOSTING MACHINE William D. Symmank, Lyon, France, assigner to Yumbo, Genas, France, a corporation of France Filed May 18, 1965, Ser. No. 456,681 Claims priority, application France, May 21, 1964, 975,365 7 Claims. (Cl. 214-147) The present invention relates in general to hoisting machines adapted to be operated at will as a loader, a crane or an excavator, more particularly to a machine of this character which is adapted to dig Wells or other relatively deep excavations.

The machine according to this invention comprises a platform, ,possibly of the type adapted to travel by translation and to swivel about a vertical axis, a boom pivotally mounted about a horizontal axis on said platform, an arm pivoted to the free end of said boom and carrying the operating tool, and hydraulic cylinders for controlling the oscillation of said boom in relation to said platform, and of said arm in relation to said boom.

According to a first feature characterizing this invention. said arm consists of two hingedly interconnected sections of which the relative angular position is controlled by means of a double-acting hydraulic cylinder adapted to either keep the outer section in a selected angular position or permit the free angular movement of said outer section.

This arrangement is advantageous in that it permits of fitting on the machine operative tools adapted during the work to develop lateral reactions, for example a shovel adapted to operate inwardly or outwardly, while facilitating the lowering of the tool to the bottom of a relatively deep excavation, for example a well being bored or sunk, the outer section of the arm being kept in this case in a substantially vertical position simply by the gravity action produced by the operating arm; of course, this last arrangement is also applicable in case the machine operates other equipments, such as a grab bucket or a hoisting hook which have but a moderate tendency to generate substantial lateral reactions.

According to another feature of the invention the double-acting hydraulic cylinder controlling the relative angular position of the aforesaid outer section is fed by means of a distributor comprising a so-called operative position in which the two chambers of the cylinder are isolated from each other and connected the one to a supply circuit and the other to a fluid discharge circuit, and a so-called neutral position in which each chamber is connected to both circuits.

The chief advantage of this arrangement is that in the so-called neutral position of the distributor the piston of said hydraulic cylinder can move freely throughout its permissible stroke since on the one hand the fluid can flow freely from one to the other chamber of the cylinder, and that, on the other hand, a possible difference in the Volume of liuid displaced in said two chambers may easily be compensated by a supply or a discharge of fluid to or from one of the supply or discharge ducts.

According to another feature characterizing this invention the aforesaid fluid discharge circuit comprises a member adapted to create a counter-pressure, this member consisting advantageously of a radiator adapted to cool the fluid.

This arrangement constitutes an advantageous complement to the preceding one and assists in avoiding the production of 'any cavitation effect due to the free displacement of the .piston in its cylinder.

According to a further feature of this invention the aforesaid member is shunted by a by-pass duct controlled 3,278,058 Patented Oct. 11, 1966 by a normally closed valve opening when the pressure in said discharge circuit exceeds a predetermined value.

Other features and advantages of this invention ywill appear as the following description proceeds with reference to the accompanying drawings illustrating diagrammatically a typical form of embodiment of the invention. In the drawings:

FIGURE l illustrates the various steps 'of the operation of a machine constructed according to the teachings of this invention, the machines shown in this igure being equipped with a grab bucket and operated for sinking a weli; and

FIGURE 2 illustrates diagrammatically the hydraulic control circuit associated with the machine of FIGURE l.

The excavator illustrated in FIGURE l comprises essentially a movable platform 18 mounted on a vertical pintle 12 carried by crawler tracks 14; this platform 10 supports a horizontal shaft 16 on which the boom 18 of the machine is pivotally mounted, the oscillation of this boom in a vertical plane being controlled by a doubleacting hydraulic cylinder 20, the body of this cylinder and its piston being ypivotally connected to the platform 10 and boom 18, respectively. The rear portion of lthe platform 18 comprises a hood or bonnet 22 enclosing the power unit of the machine, and the front portion of this platform carries a control cab 24 in which the control members are mounted.

In order to afford a clearer understanding of the mode of operation of the machine to be described presently, the boom 18 is shown on the one hand lowered to its operative position (thick lines) and on the other hand raised (thin lines). For the same reason, the movable arm denoted as a whole by the reference numeral 26, pivoted to the free end of boom 18 and carrying the excavating tool 2S, is shown in three different positions, namely its operative position (thick lines), its raised position (thin lines) and the approach position (chain-dotted lines).

The movable arm 26 consists of two sections of which the first one designated by the reference numeral 30 is pivoted on a pin 32 carried by the free end of boom 18 and adapted to be moved angularly in relation to this boom by means of a double-acting cylinder 34 having its body and piston pivotally connected on pins rigid with the boom 18 and movable arm section 30, respectively. The other section 36 of movable arm 26? consists of a cranked lever pivoted on a pin 38 rigid with the free end of the first section 30, the relative position `of the two sections of this movable arm being controlled by means of a double-acting hydraulic cylinder 40 having its body and piston pivoted on pins rigid with the aforesaid sections 30 and 36, respectively. The free end of the second section 36 carries another pivot pin 42 sup-porting the operating tool 28 which in the form of embodiment illustrated, consists of a hydraulically operated grab bucket.

FIGURE 2 illustrates diagrammatically part of the hydraulic control system of the machine shown in FIGURE l, which relates more particularly to the control of the movements of the movable arm 26; of course, the control system illustrated is completed by means for controlling the movements of the machine proper, of the boom and of the operating tool or equipment; besides, these devices of conventional design are omitted to simplify the drawing. The control system illustrated in FIGURE 2 consists essentially of a hydraulic circuit in which a substantially incompressible fluid, for example oil, is taken from a reservoir 50 by means of a pump 52 driven from the power unit of the machine, for example an internal combustion engine 54; the oil under pressure forced by the pump 52 is delivered through a duct 56 to a distributor shown in block form at 58, the various hydraulic cylinders of the machine being connected to this distributor,

although only one of them, cylinder 40, is shown in this diagram; this cylinder 40 controls the relative angular position of the two sections constituting the movable arm 26; the oil flowing from the distributor S8 is returned to the reservoir 50 through a return duct 60; more particularly, this duct 60 leads to a three way valve 62 adapted to switch the oil return either to a duct 64 leading to a radiator 66 in which the oil-is cooled by an air stream produced by a fan 68 driven from the engine 54 before returning to the reservoir 50 through a duct 70, or to a duct 72 leading directly to the reservoir 50.

The cylinder 40 controlling the relative angular posi tion of the two sections of the movable arm 26 is a double-acting cylinder consisting of a cylinder body 74 of which the blind or closed end comprises a strap 76 pivoted on a pin carried by the tirst section 30 of said movable arm 26, and of a piston 78 rigid with a rod 88 extending in a fluid-tight manner through the end wall of cylinder 74 and comprising at its outer end a trunnion 82. pivoted on a pin rigid with the other section 36 of the movable arm 26. Thus, the piston 78 divides the inner space of cylinder 74 into two chambers termed herein respectively the piston-side chamber 84 and the rod-side piston 86. The piston-side chamber 84 and rod-side chamber 86 are connected respectively through ducts 88 and 90 to the two control ports designated respectively by the reference numerals 92 and 94, of movable element 96 of distributor 58; this movable element 96 of distributor 58, of a type known per se, may comprise for example a distributor member such as a slide valve responsive to a hand lever or like manual control member 98 adapted to be set in any one of four positions designated by the reference numerals 0, 1, 2 and 3.

When the control lever 98 is placed in position 0, the movable member of element 96 of distributor 58 is in such a position that the oil simply flows through this element 96, or alternately, without considering the presence of the other elements of the distributor 58, ows directly from the inlet union or port 106 to the outlet union or port 102 of said distributor.

When the control lever 98 is in position 1, the movable member of element 96 connects on the one hand its control orilice or port 92 with the inlet union or port 100 of the distributor and, on the other hand, its control orifice or port 94 with the outlet union or port 102 of said distributor; thus, the oil under pressure is delivered through the duct 88 to the piston-side chamber 84 of cylinder 40, and the oil contained in the rod-side chamber 86 may be discharged to the reservoir S8 through the duct 90. Therefore, position 1 of lever 98 will cause the cylinder 40 to be fed on the piston side.

When the lever 98 is set in position 2 the movable member or element 96 of distributor 58 provides a fluid communication on the one hand between the control oritice or port 94 and the inlet union or port 100 of distributor 58, and on the other hand, the control oriiice or port 92 with the outlet union or port 102 of Adistributor 58. Thus, the oil under pressure is fed through duct 98 to the rod-side chamber 86 of cylinder 40, and the oil contained in the piston side chamber 84 may be forced back through duct 88 to the reservoir 50. The position 2 of control lever 98 will thus cause the cylinder 40 to be supplied with oil on the rod side.

When the lever 98 of element 96 of distributor 58 is in position 3, both control orifices or ports 92 and 94 are connected to the inlet port 100 and to the outlet port 102 of distributor S8; thus, the piston-side chamber 84 and rod-side chamber 86 of cylinder 40 are on the one hand interconnected through ducts 88 and 98 and element 96, and on the other hand both connected to the oil circulation circuit. Consequently, when the control lever 98 is moved to position 3, the displacement of piston 78 in cylinder 74 is perfectly free in either direction.

The advantages resulting from the constructional arrangements described hereinabove will appear clearly as the following description proceeds with reference to the mode of operation of the machine in the specilic application illustrated in FIGURE 1, namely the sinking of a relatively deep well.

At the beginning of the cycle of operations the machine is assumed to be in the position illustrated in thin lines, that is, with the boom 18 raised as well as the arm 26, the sections 38 and 36 of this arm being locked in their relatively aligned position; thus, the machine is moved and the boom directed with a view to lposition the pivot 38 constituting the common hinge pin of the two sections of said movable arm substantially vertically above the well being sunk. The lever 98 of element 96 of distributor 58 is then moved from the neutral position O, in which the movable sections 30 and 36 of arm 26 were locked in the position illustrated to position 1, corre-sponding to the supply of oil to the piston-side chamber 48 of the cylinder 74 or still better to position 3, in which the movements of piston 78 in body 74 of cylinder 48 are perfectly free; in either case the end section 36 of arm 26 is lowered either by the action exerted by the hydraulic iiuid under pressure acting upon the piston 78, or as a consequence of the combined gravity of the end section 36 and grab bucket 28. When the section 36 attains a substantially vertical position, the lever 98 is moved to position 3 (unless it has already been moved thereto), so that the assembly comprising the section 36 and grab bucket 28 is suspended freely from the pivot pin 38 and held in a vertical position by gravity, as shown in chain-dotted lines in FIGURE 1; then the grab bucket 28 is positioned exactly over the aperture of the well being sunk.

By properly combining the movements of the boom 18 (controlled by cylinder 2G) and of the first section 30 of movable arm 26 (controlled by cylinder 34) the bucket 28 is then lowered to its working position at the bottom of the well; it will be noted that during this downward movement of the grab bucket the assembly comprising the outer section 36 of movable arm 26 and the grab bucket 28 is properly guided by gravity alone. When the grab bucket 28 has reached its working position the lever 98 of element 96 of distributo-r 58 can be moved back to the neutral position 0, whereby the outer section 36 of movable arm 26 is locked and may thus absorb possible lateral reactions created during the work with the grab bucket 28.

Upon completion of the Work contemplated, the bucket is raised by resorting to the same sequence of operations as described hereinabove but in the reverse order, that is by properly combining the movements of the boom 18 and of the first section 30 of movable arm 26, the other section 36 being advantageously released to permit its free oscillation about the pivot pin 38 by moving the icontrol lever 98 to position 3; therefore, during the upward movement of the grab bucket 28, the assembly comprising the grab bucket and the end section 36 is held in a vertical position and properly guided by the action of gravity alone.

When the grab bucket 28 and outer section 36 have been brought back to the position illustrated in dashand-dot lines in FIGURE 1, the control lever 98 of element 96 of distributor 58 is moved to position 2 in which the cylinder 48 is supplied on the rod-side, whereby the outer section 36 of movable arm 26 is raised and brought to the position shown in thin lines, in which the bucket 28 may be easily dumped into a vehicle brought in the vicinity of the well.

As already explained hereinbefore, the control lever 96 of distributor 58 is advantageously moved to position 3 during the upward and downward movements of the working tool so that the outer section 36 of movable arm 26 be free to rotate about the pivot Ipin 38 and be thus kept in a vertical position by gravity. In fact, the oscillation of the outer section 36 of arm 26 cannot take place freely unless the movements of piston 78 in cylin` der 74 are themselves perfectly free in either direction. Referring again to FIGURE 2, it will be noted that to this end when the control lever 98 is in position 3 the pistonside chamber 84 and rod-side chamber 86 of cylinder 40 are not only interconnected through the ducts 88 and 90, but also freely connected with the oil circulation circuit; in fact, if the last-mentioned disposition were not provided the movements of piston 78 in one or the other direction would be impaired since, for a given displacement of piston 78, the volume of oil displaced in the piston-side chamber 84 differs from that displaced in the rodaside chamber 86, due to the presence of the rod 80 in the rod-side chamber 86; with the aforementioned disposition the difference in the volumes of uid displaced in these two chambers is easily compensated by taking or discharging, according to the direction of motion of the piston 78, an equivalent volume of oil in the oil circulation circuit.

Another advantageous disposition of the control system of this invention consists in inserting a cooling radiator 66 in the oil return circuit; in fact, the valve 62 normally connects the oil return duct 60 to the duct 64 leading to the cooling radiator 66, whereby the loss of pressure produced through this duct creates a counter pressure in the portion located upstream of the return circuit, this counterJpressure being of the order of 40 p.s i.,.

this pressure being communicated of course through the element '96 of distributor 58 to that chamber of cylinder 40 which, according to the position of the control lever 98, is connected to the outlet port 102 of the distributor 58. Thus irrespective of the position of the control lever 98, the pressure of the oil contained in the two chambers of cylinder 40 exceeds the atmospheric value, so that any cavitation effect is safely avoided. This disposition is particularly advantageous when the control lever 98 is moved to position 3 so that both chambers of cylinder 40 communicate on the one hand with each other and on the other hand with the oil supply circuit, and when the piston 78 is moved within the cylinder 74 by the weight of the outer section 36 of movable arm 26 and of the grab bucket 28; in this case, in fact, the movement of piston 78 tends to produce a vacuum in `one of the chambers.

In order to prevent the above-mentioned counter-pressure from becoming too high, for example as a consequence of a clogging of the radiator or of an abnormally high oil output, the valve 62 automatically opens the communication between the return duct 60 and the by-pass duct 72 when the said counter-pressure exceeds a predetermined value, for example of the order of 70 p.s.i., thus preventing any possibility of damaging the hydraulic Icontrol system.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What I claim is:

1. A hoisting machine adapted to work as a loader, crane or excavator, comprising a platform movable in translation and adapted to swivel about a vertical axis, a boom carried by said platform and pivoted thereto about a horizontal axis, an arm consisting of two hingedly interconnected sections, namely an inner section pivotally connected to the free end of said boom and an outer section carrying an operating tool, and first, second and third jack means operative for controlling the angular displacement of said boom in relation to said platform, the angular displacement of said arm in relation to said boom, and the relative angular position of said inner and outer sections of said arm, said third jack means consisting of a double acting hydraulic cylinder fed through a distributor having two working positions in which the opposite power chambers of said cylinder are isolated from each other and respectively connected to a liuid supply circuit and to a fluid discharge circuit, a locking position in which said power chambers are isolated from each other and from said circuits, and a neutral position in which each of said power chambers is connected to both of said circuits, thereby allowing for free angular displacement of said outer section in relation to said inner section.

2. A hoisting machine according to claim 1, wherein said fluid discharge circuit includes back pressure means. 3. A hoisting machine according to Iclaim 2, wherein said back pressure means consist of a radiator for cooling the fluid.

4. A hoisting machine according to claim 2, wherein said back pressure means are by-passed by normally closed, pressure responsive valve means opening when the fluid pressure in said fluid discharge circuit exceeds a predetermined value.

S. A hoisting machine adapted to work as a loader, crane or excavator, comprising a platform movable in translation and adapted to swivel about a vertical axis, a boom carried by said platform and pivoted thereto about a horizontal axis, an ann consisting of two hingedly interconnected sections, namely an inner section pivotally connected to the free end of said boom and an outer section carrying an operating tool, and first, second and third jack means operative for Icontrolling the angular displacement of said boom in relation to said platform, the angular displacement of said arm in relation to said boom, and the relative angular position of said inner and outer sections of said arm, said third jack means consisting of a double acting hydraulic cylinder fed through a distributor having two working positions in which the opposite power chambers of said cylinder are isolated from each other and respectively connected to a fluid supply circuit and to a uid discharge circuit, a locking position in which said power chambers are isolated from each other and from said circuits, and a neutral position in which each of said chambers is connected to both of said circuits, said fluid discharge circuit including back-pressure means.

6. A hoisting machine according to claim 5, wherein said back-pressure means consist of a radiator for cooling the uid.

7. A hoisting machine according to claim 5, wherein said back-pressure means are by-passed by normally closed, pressure responsive valve means opening when the uid pressure in said fluid discharge circuit exceeds a predetermined value.

References Cited by the Examiner L UNITED STATES PATENTS 1,549,508 8/1925 Robinson.

2,831,589 4/1958 Way 214-147 2,890,806 6/1959 Pilch 214-147 3,143,229 8/1964 Billings 214-147 HUGO O. SCHULZ, Primary Examiner. 

1. A HOISTING MACHINE ADAPTED TO WORK AS A LOADER, CRANE OR EXCAVATOR, COMPRISING A PLATFORM MOVABLE IN TRANSLATION AND ADAPTED TO SWIVEL ABOUT A VERTICAL AXIS, A BOOM CARRIED BY SAID PLATFORM AND PIVOTED THERETO ABOUT A HORIZONTAL AXIS, AN ARM CONSISTING OF TWO HINGEDLY INTERCONNECTED SECTIONS, NAMELY AN INNER SECTION PIVOTALLY CONNECTED TO THE FREE END OF SAID BOOM AND AN OUTER SECTION CARRYING AN OPERATING TOOL, AND FIRST, SECOND AND THIRD JACK MEANS OPERATIVE FOR CONTROLLING THE ANGULAR DISPLACEMENT OF SAID BOOM IN RELATION TO SAID PLATFORM, THE ANGULAR DISPLACEMENT OF SAID ARM IN RELATION TO SAID BOOM, AND THE RELATIVE ANGULAR POSITION OF SAID INNER AND OUTER SECTIONS OF SAID ARM, SAID THIRD JACK MEANS CONSISTING OF A DOUBLE ACTING HYDRAULIC CYLINDER FED THROUGH A DISTRIBUTOR HAVING TWO WORKING POSITIONS IN WHICH THE OPPOSITE POWER CHAMBERS OF SAID CYLINDER ARE ISOLATED FROM EACH OTHER AND RESPECTIVELY CONNECTED TO A FLUID SUPPLY CIRCUIT AND TO A FLUID DISCHARGE CIRCUIT, A LOCKING POSITION IN WHICH SAID POWER CHAMBERS ARE ISOLATED FROM EACH OTHER AND FROM SAID CIRCUITS, AND A NEUTRAL POSITION IN WHICH EACH OF SAID POWER CHAMBERS IS CONNECTED TO BOTH OF SAID CIRCUITS, THEREBY ALLOWING FOR FREE ANGULAR DISPLACEMENT OF SAID OUTER SECTION IN RELATION TO SAID INNER SECTION. 